Guidelines are proposed for the treatment of slipped upper femoral epiphysis based on the analysis of 80 cases. Treatment is strictly surgical, but the procedure to be employed depends on the degree of displacement. Major operations are reserved for maximum tilting of the epiphysis: Dunn's operation when the growth plate is still open, trochanteric osteotomy once it has closed. Complications of treatment are epiphyseal necrosis and stiffness.